1. Field of the Invention
The present invention relates to method and apparatus for having an optical recording medium containing Presentation Language (called ‘PL’ hereinafter) data, which have to be included in a digital television signal for supplementary service information in accordance with Advanced TV Enhancement Forum (called ‘ATVEF’ hereinafter) or Digital TV Application Software Environment (called ‘DASE’ hereinafter) standard, and providing the PL data contained in a recording medium for a connected external apparatus.
2. Description of the Related Art
In these days, several standards for providing various supplementary services through digital television broadcast signal are under discussion. These standards are in regard to applying Internet Protocol Language such as HTML, Java Script, CSS, and DOM to digital television broadcast signal composed of A/V (Audio/Video) signals. ATVEF standard, which is under discussion with Microsoft company as a leader, is one of them. Another developing standard is DASE which is under discussion in ATSC sub-committee.
Therefore, a digital television set is likely to satisfy ATVEF or DASE standard, which means that it can receive and process PL data included in digital television broadcast signal to provide a viewer with various additional functions.
A digital television set being able to receive PL data of ATVEF or DASE standard will be configured as FIG. 1. The digital television set 100 of FIG. 1 comprises a VSB tuner 1 tuning VSB (Vestigial Sideband)-modulated digital television broadcast signal received through an antenna, and extracting MPEG transport stream belonging to a channel chosen by a viewer from the tuned signal; an MPEG decoder 2 decoding A/V data stream contained in the extracted transport stream to original picture and sound data; and a PL separator 3 extracting PL data contained in the extracted transport stream; and a storage unit 4 such as a hard disk or memory banks for storing the extracted PL data; a PL interpreter 5 interpreting PL data stored in the storage unit 4 or received from the PL separator 3; a graphic generator 6 generating a graphic image in accordance with the PL data interpretation; and a mixer 7 mixing synchronously picture data from the MPEG decoder 2 with the generated graphic image from the graphic generator 6 to be presented together onto a screen.
The digital television set 100 configured as above tunes a digital television broadcast signal received through an antenna, decodes transport stream of a chosen channel among the tuned signal, and presents the decoded data by moving pictures and sounds. At the same time, the digital television set 100 separates PL data from the transport stream, interprets the PL data, generates a graphic image in accordance with the interpretation of PL data, and overlays the graphic image onto the displayed picture as shown in FIG. 2.
As aforementioned, PL data will have a format like Internet language such as HTML, Java Script, CSS, and DOM, and are provided for various supplementary services from a broadcast station. The PL data from a broadcast station are likely to have a syntax of ‘http://[site name] [attribute]’, for example “http://lge.com/hdvdp.html”. In ATVEF standard, uni-directional HTTP is probably applied to PL data. All or partial PL data are to be stored in the storage unit 4 for cross-referencing between HTML contents of A/V data. The PL data for cross-referencing may have a syntax of ‘lid://[namespace-id][resource-path]’, for example “lid://lge.com/hdvdp.html” or “lid://abcd/hdvdp.html”.
Owing to the PL data having such a syntax, a viewer is able to view a variety of supplementary service information for broadcasted television programs of a chosen channel through graphic images created based on the received PL data while viewing the broadcasted programs.
In addition, a high-density recording medium such as a DVD or a high-density DVD being able to store high-quality video data has been developed. Therefore, a disk apparatus for recording/reproducing television broadcast signal including PL data to/from such a high-density recording medium is under development among related companies.
However, it has not been specified how a high-density disk recording/reproducing apparatus stores PL data provided pursuant to ATVEF or DASE standard to a high-density recording medium, provides the stored PL data for a data presentation apparatus such as a digital television set, and supports PL data jointly with a digital television set. Therefore, such pending matters should be definitely settled as soon as possible.